functions_1.ex

# Basic function

defmodule A do
  def add(a, b) do
    a + b
  end
end

A.add(1, 2)
# => 3

# Guard clauses

defmodule B do
  def add(a, b) when is_string(a) do
    a <> b
  end
end

B.add("foo", "bar")
# => "foobar"

# Combine to overload functions

defmodule C do
  def add(a, b) when is_string(a), do: a <> b
  def add(a, b), do: a + b
end

C.add(1,2) # => 3
C.add("foo","bar") # => "foobar"